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GPUStack Authentication Bypass via Loopback Source Grants Admin

  1. Investigating(current)
  2. Trending(upcoming)
  3. Workaround available(upcoming)
  4. Resolved(upcoming)

Executive summary

GPUStack before version 2.2.0 contains an authentication bypass vulnerability where requests from a trusted loopback source are automatically promoted to the built-in administrator account when force_auth_localhost is False. This allows unauthenticated attackers to gain administrative privileges via a same-host reverse proxy or X-GPUStack-Real-IP header spoofing.

No verified workaround yet

None of the linked reports describe a mitigation. Follow this incident to hear when one appears.

Official fix
Technical root cause

The `get_current_user` function in `gpustack/api/auth.py` evaluates request sources and incorrectly promotes requests to the admin account if they appear to originate from loopback, relying on client IP resolution that can be spoofed via reverse-proxy TCP peers or the X-GPUStack-Real-IP header.

Evidence

1 report · 1 CVEShow
  1. [1]
    CVE First report
    GPUStack: Authentication bypass via trusted loopback source (reverse-proxy TCP peer or X-GPUStack-Real-IP header) grants unauthenticated admin(opens security advisory in a new tab)

    Fixed in: gpustack 2.2.0. Critical severity (CVE-2026-102895). Affected: gpustack (pip) < 2.2.0. ### Impact In GPUStack before v2.2.0, `get_current_user` (in `gpustack/api/auth.py`) promotes any request whose source is considered loopback to the built-in administrator account when `force_auth_localhost` is `False` (the default). The "source" is derived by `client_ip_getter`, which can be made to report `127.0.0.1` without any credentials in two ways: 1. **Same-host reverse proxy (TCP peer).**…

    by GitHub Advisory Database 0upvotes 0comments

Timeline

  1. First report on security advisory

    GPUStack: Authentication bypass via trusted loopback source (reverse-proxy TCP peer or X-GPUStack-Real-IP header) grants unauthenticated admin

    Source